This invention relates generally to providing enhanced functionality with regard to common radio frequency identification (RFID) technologies and devices, and more specifically, to the utilization of electromagnetic flux fields of at least one predetermined radio frequency (RF) to detect various geometric alignment conditions of two or more items, devices, or apparatus to each other in three dimensional space, for example, as an x-ray system positioning apparatus, the invention provides for detection and indication of the relative positionings, ergo: various geometric alignment conditions, as might exist between an x-ray emissions device, and, an RFID tag coupled with an x-ray sensitive film or apparatus.
In general, function of a given RFID tag is to act as a “remote sensor device” for a given RFID transponder (ie: an electronic apparatus which is coupled to an RF sense coil). When enabled, an RFID transponder's sense coil (also known as a carrier transmit/data receive coil, or reader), produces an electromagnetic field of flux at a predetermined frequency, which creates a radiated “carrier” transmit signal. When an RFID tag is placed in close proximity to an enabled RFID transponder's sense coil, the RFID tag eventually “powers up”. The RFID tag, being impressed with the carrier transmit signal, becomes activated. This occurs by the fact that an LC tank circuit, generally comprised of a capacitor and a carrier receive/data-transmit coil, within the RFID tag begins to self-oscillate, which creates a secondary electromagnetic (EM) field of flux at a predetermined frequency within and about the RFID tag. Soon after the RFID tag is activated, the RFID tag begins to transmit a serial data stream of “canned/stored” information. Data transmission is generally accomplished by means of electronic components within the RFID tag shunting the LC tank circuit, according to the RFID tag's design criteria and predefined data protocol, etc.
When an RFID tag begins to oscillate so as to radiate a specific RF signal and electromagnetic field of flux, the RFID transponder sense coil becomes impressed with the RFID tag's “return” RF signal. The return RF signal impressed upon the RFID transponder sense coil is commonly referred to as “backscatter” or a backscatter signal. In concert with effects produced by “near-field inductor coupling”, the backscatter signal generally alters certain characteristics of the RFID transponder carrier-transmit signal. Such carrier-transmit signal alterations, even as they might be minute initially, can be detected by appropriate RFID transponder “front-end” circuitry. When actual RFID tag serial data stream transmission occurs, the RFID transponder acts to detect the backscatter signal, generally, through the use of an “envelope detector” circuit. The RFID transponder will then condition/filter and amplify the backscatter signal to obtain a resultant “clean” data stream signal. Thereafter, the RFID transponder's microcontroller may “test/decode/read” and be configured to respond to the resultant signal, for example, by inputting a product name, code and price into a cash register when an item containing an RFID tag is scanned, or by setting off an alarm when someone walks out of a store without purchasing an item containing an RFID tag. However, current RFID technology has routinely been limited to its namesake: product “identification”. Thus, the technology has not been applied in alternatively new ways, or with regard to differing applications. Accordingly, common RFID technology does not provide for geometric alignment functionalities, such as indicating best non-contact alignment between an x-ray emitter and an x-ray film during the positioning of one to the other.
During the traditionally standard process of taking dental x-rays, special tools and several tedious steps are often required. Two options for taking x-rays are well known wherein: 1) a molded x-ray film holder, which generally has sharp edges around its periphery, is loaded with an x-ray film and together is placed in a patient's mouth to bite down on (which is most discomforting for most patients due to the sharp edges), such that a dental technician or doctor must then visually estimate the position of the film holder so as to take an x-ray; or, 2) wherein a molded x-ray film holder, also having sharp edges around its periphery, is loaded with an x-ray film and together is placed onto a “RINN SYSTEM” apparatus (a long bar, generally of metal, with an x-ray film holder receiving device at one end, and an x-ray “head” apparatus receiving device at the other end), which is then collectively placed in a patient's mouth to bite down on (which is extremely discomforting for most patients due to the sharp edges, as well as due to the bulkiness of the RINN apparatus) with the metal bar and x-ray head apparatus receiving device protruding from the patient's mouth such that a dental technician or dentist would then place the x-ray head into the x-ray receiving device so as to take an x-ray radiograph.
Aside of the general need for special alignment tools, the disadvantages of the above two options are several: 1) often additional x-rays are required to be taken because of improper alignment of the x-ray head apparatus to the x-ray film, especially when the location/position of the x-ray film is manually estimated, and often, when; 2) the RINN SYSTEM is improperly located/positioned in a given patient's mouth, which creates; 3) loss of both time and supplies, increasing expense, and, which additionally; 4) exacerbates a given patient's discomfort. The present invention was devised to overcome these challenges with graceful simplicity. The first concept considered was to provide a system that might permanently eliminate the need for a RINN SYSTEM device/alignment tool. The second concept considered was, in part, to alter the design of the common x-ray film holder device so as to eliminate its sharp edges, and provide means to accurately locate/detect it's position, as attached with an x-ray film, once hidden inside a patient's mouth. The third concept was to identify a system by which the taking of dental x-rays would become less intrusive, yet more accurate.
RFID technology appears to offer the most ideal solution to the current challenges associated with obtaining dental x-rays, yet-RFID technology, in practice and application, has customarily been used for product and other commodity “identification” purposes. Such technology had not been used for exacting a critical alignment of an x-ray head apparatus to an (often hidden) x-ray film. One aspect unknown in the prior art was a system that would permit placement or attachment of a predetermined RFID tag (aka: RF tag) on or about a common x-ray film or x-ray film holder device. Such a system would also provide for RF tag placement or attachment to or about newer technology (ie: digital radiograph sensors). In this, an enhanced RF tag architecture and device is required, as are various methodologies with which to embed or place the new RF tag.
Another aspect unknown in the prior art is an electronics design that would act as a dental RFID transponder (aka: RF transponder), and that could have a remote yet attached sense coil. Such a coil, which acts to enable the new RF tag device and also acts to receive data from an enabled new RF tag device, would need to be devised so as to fit upon/mechanically interface to the active end of a given dental x-ray head apparatus.
One issue in creating a dental-oriented non-contact RFID transducer system is that a given dental RF tag ought be physically smaller than an accompanying dental RF carrier transmit/data receive coil. Another issue to operational practicality for a dental application is that “non-contact” operation be obtained, wherein a given x-ray head apparatus would never (intentionally, nor need to be caused to) touch a patient's face, in the course of alignment of the x-ray head apparatus to the dental RF tag within a patient's mouth. This issue is not in the least trivial since known RFID technology did not allow for spacious RF tag distance sensing in wholly scaled-down RFID systems. Various common RF tags currently available were used in test beds, and were found to be grossly lacking as it concerned desired functionality and operational distance to a similarly available RF transponder.
It was found that when an RF tag was placed in a patient's mouth and behind the teeth (as would normally occur in a dentist's office), valid sensing-distance was no more than one inch, and often much less. An RF transponders carrier transmit/data receive coil needed to be placed inward on, at, or extremely close to the cheek in order to “read” a common RF tag. Thus, commonly available systems were both non-ideal and impractical for a dental x-ray application. Therefore, there is an additional need for an enhanced RF transponder circuit design having additional features, and an enhanced carrier transmit/data receive coil circuit design.
As will be appreciated by those of skill in the art, providing.a dental x-ray RFID positioning and alignment system incurs several design challenges, including: 1) dental RF tag size, which being rather small, produces only a small RF field of flux at resonance; 2) sensing distance to a given RF tag of at least two inches is desirable; 3) dental RF transponder carrier transmit/data receive coil size, which also being rather small, has a limited range for detecting a radiated RF signal from a remoted RF tag when an RF tag is activated; 4) data stream signals received by a dental RF transponder carrier transmit/data receive coil are often in the microvolt range when the RF tag is several inches away; 5) such signals, when then fed into operational amplifier circuits, generally can not be distinguished or easily separated from base-noise levels of operational amplifier circuits, and thus, 6) the resultant signals from the operational amplifier circuits contain inherent and free-air radiated noise, as well as the desired data signals, and also include RF carrier transmission components, making “valid” signal detection difficult; and 7) even with filtering, free-air radiated alternating current (A.C.) signals are amplified and become part of the net/final signal structure from the operational amplifier circuits, thereby, grossly affecting final signal integrity, particularly when obtained by a highly sensitive RF transponder analog front-end circuit.
Thus, what is needed and heretofore unknown is an RFID transducer non-contact alignment system that fulfills dental and other x-ray application requirements, that solves the above identified technical challenges, and that provides cost effective simplicity of operation. There is also a need for RFID-type technology operable over greater distances between certain types of RF tags and RF transponders. There is also a need to fill the technological gaps and voids in the practical applications of RFID technology. There is a further need for an ability to offer RFID alignment functionality to establish and provide for new applications within the RFID industry, especially with regard to the critical alignment of two or more items, devices, or apparatus to each other in three dimensional space.